Irrigators rely on channels for delivery of water to areas where crops are grown. Such areas may have a laser-levelled surface so that an inbuilt incline ensures the water runs to the end of the channel whenever water is available.
When a head develops in the water supply network, the end of the channel overflows. If this continues, the ground surrounding the overflow site becomes muddy and the roots of the growing crop lack air and die. The grower loses a percentage of the crop and the muddy area is an obstacle to the free movement of the wheels of irrigation equipment.
The flow in the channels is ensured by bulk water delivered to the channels through pipes. In related Australian Patent Serial No. 2013902571, float-operated valves are described that include a rise and fall stop gate capable of stopping flow in the pipe supplying an installation such as a LINDSAY® overhead irrigation device.
U.S. Pat. No. 1,343,871 describes a system for supplying water to different parts of a field by a pipe that fills a group of containers, each with its own float valve to allow water to flow to subsidiary boxes. A ball float on the end of an arm that progressively closes a valve to a valve seat stopping the flow is out of sight inside the container.
U.S. Pat. No. 2,362,747 describes a chain of tanks, each with an outlet for discharge into a soil channel. A control tank in the chain contains a float valve that opens and closes a valve in a pipe that supplies the whole chain.
U.S. Pat. No. 6,953,156 describes a system for irrigating sloping land. This too relies on a ball-type float valve that controls water entry into a distributor tank from which branch pipes flow to different areas depending on their slope.
The ball valves used for these systems cannot be inspected and maintained easily.